Inputs
Geometry (per metre length)
m (top of stem to base of slab)
m
m
m
m
m
Soil & Loads
degrees
kN/m³
kPa
m above base for passive
kPa
tan δ ≈ 0.5–0.7
kN/m³
MPa
Method & assumptions
- Active pressure: Ka = tan²(45−φ/2) (Rankine, vertical wall, level fill).
- Passive: Kp = tan²(45+φ/2). Use FSpassive ≥ 1.5 in design.
- Surcharge contributes uniform Ka·q over height.
- Stability target FS: sliding ≥ 1.5, overturning ≥ 2.0, bearing capacity envelope.
- Bearing pressure trapezoidal (Meyerhof) about heel; tension implies eccentricity beyond kern.
- Stem flexural design: compute M and V at base of stem (per metre).
- Heel slab self-weight + soil + surcharge above heel resist overturning (positive).
Results (per metre length)
Ka / Kp—
Active Force Pa (soil)—
Surcharge Force Pq—
Total Driving Force Hd—
Total Vertical W—
FS Sliding—
FS Overturning—
Eccentricity e—
qmax / qmin—
Stem M / V at base—
StatusOK